ML19341C808
| ML19341C808 | |
| Person / Time | |
|---|---|
| Site: | Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png |
| Issue date: | 01/13/1981 |
| From: | Crutchfield D Office of Nuclear Reactor Regulation |
| To: | Counsil W CONNECTICUT YANKEE ATOMIC POWER CO. |
| References | |
| TASK-08-01, TASK-8-1, TASK-RR LSO5-81-01-019, LSO5-81-1-19, NUDOCS 8103040217 | |
| Download: ML19341C808 (4) | |
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Docket tio. 50-213 RPurple b.: .I _. h DEisenhut h
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Mr. W. G. Counsil, Vice President RTedesco
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Dear Mr. Counsil:
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SUBJECT:
SEP TOPIC VIII-1, DEGRADED GRID VOLTAGE - REQUEST FOR ADDITIONAL IiiFOR!1ATION a
As a result of our review of your August 21,1980 submittal and a conference call on October 7,1980 on this subject we have
,i found that additional information is necessary to complete our review. We, therefore, request that you provide the inforniation specified in the attached enclosure wic..in 45 days of your receipt of this letter.
Sincerely, 1
Cennis M. Crutchfield, Chief Operating Reactors Branch #5 Division of Licensing t
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January 13, 1981 Docket No. 50-213 LS05-81-01-019 Mr. W. G. Counsil, Vice President Nuclear Engineering and Operations Connecticut Yankee Atomic Power Company Post Office Box 270 Hartford, Connecticut 06101
Dear Mr. Counsil:
SUBJECT:
SEP TOPIC VIII-l, DEGRADED GRID VOLTAGE - REQUEST FOR ADDITIONAL INFORMATION f
As a result of our review of your August 21, 1980 submittal and a conference call on October 7,1980 on this subject we have f
found that additional information is necessary to complete our i
review. We, therefore, request that you provide the information specified in the attached enclosure within 45 days of your receipt of this letter, Sincerely, i
/W W-Dennis M. Crute ield, hief Operating Reactors Br nch #5 Division of Licensing
Enclosure:
Request for Additional Information cc w/ enclosure:
See next page
Mr. W. G. Counsil January 13, 1981 B
cc Day, Berry & Howard U. S. Environmental Protection Counselors at Law Agency One Constitution Plaza Region I Office Hartford, Connecticut 06103 ATTN: EIS COORDINATOR JFK Federal Building Superintendent Boston, Massachusetts 02203 Haddam Neck Plant 2
RFD #1 Resident Inspector Post Office Box 127E Haddam Neck Nuclear Power Station East Hampton, Connecticut 06424 c/o V. S. NRC
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East Haddam Post Office Mr. James R. Hiarelwright East Haddam, Connecticut 06423 Northeast Utilities Service Cocpany P. O. Box 270 Hartford, Connecticut 06101 l
Russell Library 119 Broad Street Middletown, Connecticut 06457 Board of Selectmen Town Hall
- j Haddam, Connecticut 06103
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.i Connecticut Energy Agency ATTN: Assistant Director I
Research and Policy Development Department of Planning and
'j Energy Policy 20 Grand Street Hartford, Connecticut 06106 Director, Criteria and Standards Division Office of Radiation Programs (ANR-460)
U. S. Environmental Protection Agency Washington, D. C.
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REQUEST FOR CLARIFICATION AND ADDITIONAL INFORMATION HADDAM NECK - DOCKET N0. 50-213 i
DEGRADED GRID AND ADEQUACY OF STATION ELECTIRC DISTRIBUTION SYSTEM VOLTAGES Reference 1: CYAPC0 Letter (D. C. Switzer) to NRC (A. Schwencer) dated September 30, 1976 Reference 2: CYAPCO Letter (W. G. Counsil) to NRC (D. L. Ziemann) dated September 24, 1979 I
Reference 3: CYAPC0 Letter (D. C. Switzer) to NRC (A. Schwencer) dated July 21,1977 I
Reference 4: NRC Lettar (A. Scin encer) to CYAPCO (D. C. Switzer) dated June 3,1977 Reference 5: CYAPCO Letter (W. G. Counsil) to NRC (D. M. Crutchfield) dated August 21, 1980 4
Reference 6: NRC Letter (W. Gammill) to All Power Reactor Licensees, dated August 8,1979
'g Reference 7: Telephone Conference Call with John Ferraro, Tim Murray, Ralph Caruso (NRC), Iqbal Ahmed (NRC), Jim Selan (LLNL),
Bob White (LLNL), October 7,1980 l
In Ref. 5 the licensee has proposed two second-levels of undervoltage protection.
with the following setpoints:
a)
First second-level protection at 3940 volts (94.4% of 4160 volts) for nine seconds.
b) Second second-level protection at 4028 volts (96.8% of 4160 volts) for nine seconds.
t In a telephone conference on October 7,1980 (Ref. 7) the two second-levels of
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undervoltage protection were discussed. The following are points of concern from Ref. 5 and Ref. 7.
- 1. For an SI signal, both of these second level protection schemes would be blocked and will only be reinstated when SI signal is reset. This blocking removes the the protection of the Class lE equipment should a degraded grid condition exist during an accident condition until the loss-of-voltage protection scheme setpoints l
are reached (2870 volts - 69% of 4160 volts). The Class 1E equipment must be protected against sustained degraded voltages per staff Position 1 of Ref. 4.
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j The bypassing of the degraded grid protection scheme during the time period
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that an SI signal is present is a direct contradiction of the lessons learned from the original Millstone event and is therefore unacceptable.
2.
The two second level setpoints are considered to be too high to preclude spurious trips during the starting of a large non-Class lE load required by Guideline 3 and 9 of Ref. 6.
Please provide justification for these setpoints and explain how spurious trips are prevented from occuring.
3.
The 4.160 volt non-Class 1E tie breaker, 2T3 between redundant load groups will automatically close when one of the two 115 Kv/4160 volt transformers is out of service. The selecting of either the first second-level protection scheme or the second second-level protection scheme and enabling the selected scheme is a manual operation. Manual actions associated with enabling / disabling the second level protection scheme associated with the unlikely and infrequent configuration of having only one 115/4.16 kv transformer may be acceptable.
However, the normal two transformer configurations should meet the requirements of Staff position 1 of Ref. 4 (i.e. the protection scheme shall be initiated automatically).
Provide further details on this aspect of your proposed design as well as supporting bases and justification.
4.
In Ref. 7, it was stated that s 1ximately 113 kv would have to be maintained on the grid to keep the Class -
60 volt bus above the second second-level setpoint (97%) in the case wher, one service transformer is available.
Explain what administrative proce.
or limiting conditions of operations would be used to maintain this gri ultage.
5.
The previously proposed degraded grid protection scheme-included an alarm annunciator system. Clarify in detail the integration of the proposed two second-levels of undervoltage protection with the alarm protection system with its associated administrative procedures and limiting conditions of operation, r